If youre running a Ruby on Rails application on a shared host, its super-double-plus recommended to freeze your Rails. Freezing your Rails means putting the framework into vendor/rails instead of floating with whatever gems that are installed on the host. Because if you do so, youll automatically be upgraded when they are. Not a great thing for a production application to have forced upon itself.
The great news is that this is silly simple. If youre running 0.14.x or newer, you can simple do
rake freeze_gems, and the current gems the system is used are unpacked into vendor/rails. Now the host can update as silly as it wants without affecting your application. [Riding Rails]